What is 45 100mm on medium format in full frame?

45-100mm on medium format gives the view of 36-79mm on full frame.

The same view on every common format:

• Medium format (44 x 33) (yours): 45-100mm
• Full frame: 36-79mm
• APS-C: 24-53mm
• APS-C (Canon): 22-49mm
• Micro Four Thirds: 18-40mm
• 1-inch: 13-29mm
• 1/1.3-inch: 9.9-22mm
• 1/1.7-inch: 7.7-17mm
• 1/2.3-inch: 6.3-14mm

Crop factors are by the sensor diagonal, rounded as they're usually quoted; a format with a different shape (4:3 against 3:2) frames a little differently across the width. More in the focal length converter.

Computed from the sensor sizes, not written by a model.